Board for mounting display element

ABSTRACT

A board usually resembling a PCB or a PWB mounts a display element, whose appearance in a viewing direction is controlled by the sense of magnetization of a core which extends through a bore in the board. A conducting coil formed on the surface of said board is located so that current in said coil will magnetize the core.

This is a Continuation of application Ser. No. 08/851,889 filed May 6,1997.

This invention relates to electromagnetically operable display elements,and to a novel means of operating and mounting them.

Such display elements are exemplified by: anyone of those shown in:

    ______________________________________    U.S. Pat. No.   2050325      Browne    U.S. Pat. No.   RE 35,357    Browne    U.S. Pat. No.   5,337,077    Browne    U.S. Pat. No.   4,566,210    Winrow    U.S. Pat. No.   5,156,872    Helwig    ______________________________________

whose contents are incorporated herein by reference. The devices in suchpatents are examples of such elements, wherein an electromagnetic coreis switched in magnetic polarity by a coil surrounding the core. Thedisplay element switches between OFF to ON state responsive to a changein core polarity. In OFF state a rotor or other moving element displaysone appearance (usually dark) in the viewing direction, and acontrasting appearance is displayed, which is usually bright, in ONstate. For example:

    ______________________________________              Viewing Direction                             Viewing Direction    U.S. Pat. No.              Appearance in ON State                             Appearance in OFF State    ______________________________________    2050325   Bright Disk Side                             Dark Disk Side              with LED       LED shuttered    RE 35,357 Bright Disk Side                             Dark Disk Side              with Fibre Optic                             Optic is shuttered    5,337,077 Fibre Optic    Optic is shuttered    4,566,210 Bright side of Bright side is              Lever          hidden    5,156,872 One side of Disk                             Contrasting Side of                             Disk    ______________________________________

In each of the above examples the cores are wound with helical coils toprovide the magnetizing turns. A separate means is provided for mountingthe display elements whether as single indicators, rectangular modulesor large arrays or other arrangements. The mounting means involvesconsiderable expense.

In accord with this invention an insulating board is provided withconducting paths formed on a surface thereof which paths act as a turnor a series of turns about a core. The final insulating board may be alamination of a number of sub layers of such boards if the number ofturns requires more turns than can be conveniently placed on onesurface. The conductors are arranged relative to an aperture for a core.The `flat coil`, so called to differentiate it from the usual helicalcoils, may be prefabricated on a surface of the insulating board or itslayers. Hence the step of winding is eliminated. A flat coil of morethan one turn will include a spiral which need not be geometricallyregular. The number of turns on any one surface is limited by the factthat there is a limit for spiral size set when the outer turns do nothave a successful magnetization effect.

Moreover the cost of a module or array is reduced since the board may beprefabricated with an array of core apertures which may be used to mountthe cores and achieve the arrangement of the display elements in amodule or array. The display element comprising the stator and rotor maybe mounted on the board. The cost of a former mountings for element,module or array as encountered in the prior art is eliminated. By"board" herein is meant a relatively flat board of (preferably),dielectric material commonly used to mount circuits, or circuitcomponents, and is here used to receive the flat coils. Preferably, theboard is of the same material as those commonly used for printed circuitboards or printed wiring boards and is commonly made offiberglass-filled epoxy resin, although boards formed from othermaterials may be used. The board as described herein is used to mountthe flat coils and the display elements in desired relationship to thecoils and to each other. `Board` herein includes a lamination of sublayers of thinner boards.

By `flat coil` herein, I mean a pattern of thin ribbon or filmconductors formed on the surface of a board layer or on sub-layersthereof to magnetize a core passing through the board within themagnetic field of the coil. Thus, the magnetization will be in oppositesenses for opposite current flow through the coil. A `flat coil`includes a series of coils surrounding a common bore but arranged ondifferent sub layers of the board.

Commonly the pattern of film or ribbon is formed on the board bycovering it with attached metal foil and etching away the portion notdesired for the pattern. The foil is usually of copper. The invention isnot however dependant on the method of forming the laminated conductoron the board. Thus, this conducting patterns may be supplied bypainting, printing or deposit where commercially practical methods areavailable. A conductor or copper or other metal may be provided with asurface of tin or precious metals for better electrical contact.

A `pin` is that part of a core which magnetically drives or retains themoving member of a display element. The first three patents listed onpage 1 show display elements using two pins on the core while the lattertwo elements show display elements with a single pin on the core. Thepins may also act as stops for the movable member in some displayelements.

In drawings which illustrate a preferred embodiment of the invention:

FIG. 1 shows a typical display element mounted on a board. The elementis in ON position,

FIG. 2 shows the same view as FIG. 1, except that the element is in OFFposition,

FIG. 3 shows one method of mounting the display element on a board,

FIG. 4 shows another method of mounting the display element on a board,

FIG. 5 shows the conductor arrangement on a board,

FIG. 6 shows an enlarged section of a conductor,

FIG. 7 is a section of a multilayer board,

FIG. 8 is a schematic view showing the wiring on a multilayer board,

FIG. 9 shows a board with core mounting bores for a part of an array,and

FIG. 10 shows a board with elements in place for part of an array.

In the drawings: the display element is exemplified by a statorcomprising: a housing 10 having mounting posts 12 and magnetizableremanence stator pins 14 and 24 forming opposite ends of a core. A rotor17 is mounted to pivot about an axis 15 transverse to the viewingdirection V. The rotor in this embodiment rotates between an ON and OFFposition as determined by stops which may be separately provided or maybe provided as here by the ends 14E, 24E of pins 14 and 24 respectively.The invention includes rotors or movable members which do not requirestops.

In ON position the element displays a bright face 20 in the viewingdirection and in OFF position the element displays a dark face 22. (FIG.10)

In the element shown a magnet 16 located in the disk which is activated,when pin end 14E is positive and pin end 24E is negative, to move to ONposition; and when the polarities are reversed to move to OFF position.

In the embodiment shown the two pins 14 and 24 are mounted in the bores30 and 32 respectively of FIG. 3 and the element may be mounted on thecores. However, the display element receiving the pins 14, 24, as shown,may also be mounted on the board by separate means not shown. The pinsare connected by the integral extent 32', or may be connected by a lateradded extent 33 (FIG. 4) and may be inserted from the top.

(Another display element such as those exemplified on page 1 wouldprovide analogous features as those described).

In accord with the invention a board 35, preferably of fiber glassfilled epoxy resin, is provided with hole pairs 30, 32 (FIG. 5) whichcorrespond to positions for the display element, as indicated in dottedsquares 34 on FIG. 9 (where the current paths are omitted), to make thearray partially shown in FIG. 10 (With a differently shaped ordimensional display element shape of the areas or sizes of the elementson the board will of course be different).

The stators may be mounted by pushing the pins 14, 24 on the U shapedmember through the board, and the pins may be attached to the housingand to the board by friction or adhesive.

Alternatively, the pins may be attached to the board as separate membersand provided with a bridging member to form the core.

The pin lengths will normally be of magnetic material with magneticremanence so that their magnetic polarity is retained after anenergizing pulse. It is not necessary that the bridging member be: hardor high remanence; magnetic material.

FIG. 8 shows in exploded view means for combining board into a luminateboard to provide more windings associated with a given core bore 30 withextents 30A, 30B, 30C in a section of the multilayer board with sublayers A,B,C as shown in FIG. 7.

As shown, the current (pulse) supply may be brought on a foil conductor41A to the clockwise inward spiral 43A on board sub layer A to provide aclockwise current flow about a core 14 in bore extent 30A. To add to theturns for a core in bore 30A, 30B may be provided in sub layer B aboveor below (here below) A. Although the current paths have an insulatingcoating 49 (FIG. 6) which avoids shorting with paths 47 on a facinglayer of the adjacent board, it is presently preferred to have a boardsub layer between each conductive path. Accordingly, on board sub layerA, the inner end of the spiral is attached to a connector 46A extendingthrough the board to a position on board sub layer B having the sameazimuthal relationship to its aperture 30B as the pin's relation to theaperture 30A on layer A. In FIG. 8 the flat ribbon shape of theconducting path is omitted.

For addition of the magnetizing field on sub layer A to sub layer B,layer B must also provide a clockwise spiral path about bore 30B to thecurrent in the direction shown. At the outward end of the layer B spiralthe conductor is attached to connector 46B passing through layer B forattachment in the same azimuth position to the outer end of the spiralon layer C.

Thus board C may provide a clockwise inward spiral for addition to turnsof the coil of layer C to those of A and B.

Since the layer C spiral has clockwise inward and clockwise downwardspiral, it will be obvious that it represents a repeat of the layer Acycle so that the drawing represents 11/2 stages. Thus the stages may becontinued and the number of turns as desired accumulated as required.

With the flat coils on the various sub layers connected in series themagnetization effects in the various sub-layers may be added if the sublayers are arranged so that current in the series connected flat coilstravels in the same sense (i.e. clockwise or counter-clockwise) aboutthe core, independently of whether an individual coil spirals in or out.

Thus current flow in one direction through the series connected coilswill create a North Pole at the pin end 14E in the display elementhousing while current flow in the opposite direction will create a SouthPole at pin 14E

If the display element requires two drive pins (as in the displayelement of FIG. 1 and the first three patents on page 1), the coilsarranged on the board layers surrounding the bore 32 will create theopposite magnetism to pin end 24E to the pin end 14E in bore 30.

Thus the sense of the turns is thus same for the coils about the pin 24which may be threaded through aligned sub layers if they exist. Thus,the layers shown will have analogously connected spirals about alignedbores as in FIG. 1 but directed for current flow in the oppositedirection for the other pin 24. The winding current directions discussedare those for one of the ON or OFF positions of the display element. Forthe other of the ON or OFF positions the current direction will ofcourse be reversed.

On FIG. 5 a foil conductor 41A leads into the clockwise inward spiral43D where it conducts current in a clockwise looking downward spiralabout bore 32 and a pin 24 not here shown, located herein. At the inwardend of the spiral the foil conductor is connected to connector 46A whichextends through the board 35 to the foil connector 47 on the bottom ofboard 35. At the left hand end of connector 47 the connector 47 isconnected over connector 45B to the foil path 41B of counterclockwiseoutward of spiral 43E where with foil path 41A it goes to the voltage orcurrent source.

It will be seen that the coils are arranged and connected so thatcurrent in the direction of the arrows shown will magnetize the pin inbore 30 in one sense and the pin in bore 32 in the opposite sense. Thus,if the current in the foil paths is reversed, both pins will be switchedto opposite polarity but will still be opposite polarity to each other.

It will be noted that if the spiral flat coils 43E and/or 43D arereplaced by series connected coils as shown in FIG. 8, that these seriesconnected coils will be respectively connected to the voltage source atone end and at the other end to the connector 47.

FIG. 6 shows an enlarged somewhat schematic view of the foil paths 41Aand 47 connected by connector 45A through the thickness of board 35.

The flat coils are, as stated insulated but their innermost extents areset back from the bores 30 or 32 to avoid the risk of shorting thecoils.

The flat coils are considered as approximately arranged in a planecorresponding to the median plane of the board whether arranged as asingle board surface or in series of coils on a plurality of sub layers.

The invention has potential use for all applications wherein a coil ispresently used to magnetize a core to `set`, `reset`, or switch adisplay element. Other features of a typical display element may beadded to the arrangement shown without change or at least without unduemodification.

Illustrating this by reference to the exemplary patents listed on page1: with reference to U.S. Pat. No. 5,050,325 the arrangement shown mayreplace the wound coil with the flat coils for an element provided withLEDs to augment the `ON` appearance. Similarly the inventive arrangementwill accommodate fibre optics as shown in patents RE35,357 or U.S. Pat.No. 5,337,077 where a fibre is combined with a disk or a shutter, ofU.S. Pat. No. 4,566,210 where a single pin may be energized by flatcoils arranged about a single bore where the core drives the bright faceof a lever between exposed and occluded position.

U.S. Pat. No. 5,156,872 exemplifies a disk operated element using asingle pin. For use with the flat winding each space on a boardcorresponding to a display element would have a single core-hole andflat winding.

We claim:
 1. A board formed of one or more layers,a magnetizable coreprojecting through a bore in said board, a display element displayingcontrasting appearances in a viewing direction responsive to thedirection of magnetization of said core, a conducting coil formed on alayer of said board arranged to magnetize said core in a sensedetermined by the direction of current flow in said coil.
 2. A board asclaimed in claim 1 wherein said coil forms at least one turn about saidbore.
 3. A board as claimed in claim 1 wherein said core includes alength with magnetic remanence which retains magnetic polarity after anenergizing pulse.
 4. A board as claimed in claim 1 wherein said layer ismade up of a plurality of sub layers and wherein said coil is shaped toform at least two spirals located on different sub layers of said boardand wherein said at least two spirals are connected in series so thatcurrent in both coils magnetizes said core in the same sense.
 5. A boardas claimed in claim 1 wherein said core includes two pins received inspaced bores in said board the coils surrounding said bores beingconnected and shaped so that the magnetization of each pin is oppositeto the other for either direction of current flow.
 6. A board comprisingat least one layer, at least one bore through said layer, containing acorea thin conducting path on said board providing a current path, saidpath having shaped to magnetize said core in a sense dependant thedirection of flow of current in said path, a pin forming part of a coreconnected in said bore, and a display element mounted on said boardadapted to display one appearance or another in response to themagnetization of said pin.
 7. A board as claimed in claim 6 wherein saidpath is located on the surface of a layer or at least one sub layer. 8.A board as claimed in claim 6 wherein said path forms at least one turnabout said bore.
 9. A board as claimed in claim 6 wherein said board ismade up of a plurality of layers and wherein said path is shaped toprovide at least two spirals located on different layers of said board,wherein said at least two spirals are connected in series so that thecurrent in each coil tends to magnetize said core in the same sense. 10.A board as claimed in claim 6 wherein two spaced bores withcorresponding pins are provided and there is provided a pathcorresponding to each pin, said paths being connected in series andshaped so that the magnetization of pins in the respective bores isopposite to the other for either direction of current flow.
 11. Aboard,a bore therethrough, a pin located therein a thin conducting layeron said board proving a current path, said path being shaped tomagnetize a pin located in said bore in a sense dependant on thedirection of flow of current in said path, a display element mounted onsaid board adapted to display one appearance or another in response tothe magnetization of said core.
 12. A board as claimed in claim 11wherein said core will have sufficient remanence to retain its magneticpolarity after an energizing pulse.
 13. A board as claimed in claim 1wherein a display element stator is mounted on said board by locatingsaid extending core through the board and attaching such core to theboard.
 14. A board as claimed in claim 6 wherein a display elementstator is mounted on said board by locating said extending core throughthe board and attaching such core to the board.
 15. A board as claim inclaim 11 wherein a display element stator is mounted on said board bylocating said extending core through the board and attaching such coreto the board.
 16. A board having at least one layer fabricated with abore arranged in a pattern to form part of an array of displayelements,at least one bore corresponding to each display elementposition in said part of said array, a conducting path formed on suchlayer corresponding to display element position in said port, a bore insaid board corresponding to each position, said bore arranged so that acurrent in said conducting path corresponding to a display element maymagnetize in a core in a bore corresponding to the same display element,in a sense determined by the direction of flow of current in said path.17. An array made up of display elements which include a correspondingmagnetic core where each element displays one of two contrastingappearances in a viewing direction as selectively determined by thepolarity of the magnetic core, an arrangement of elements in said arraycorresponding the bores in a board, each arranged to receive a magneticcore,wherein conducting paths are formed on a surface of one of a layeror sublayer of said board, a path corresponding to a bore being arrangedto magnetize a core therein in a direction determined by the directionof current flow in said path.
 18. A board as claimed in claim 16arranged to define an array comprising rows and columns of displayelements.
 19. A board as claimed in claim 17 arranged to define an arraycomprising rows and columns of display elements.